How do we put an invoice into the system that we have not paid for yet from last year? Thank you.

Thanks for visiting the Community for your concern, @richardwakefield.

When invoices become uncollectible, you'll have to record them as a bad debt and write them off to ensure your accounts receivable and net income stays updated.

First off, we need to create a bad debt expense account. Here's how: 

1.  Go to the Settings menu, then select Chart of Accounts.
2. Select New to create a new account.
3. From the Account Type dropdown menu, select Expenses.
4. From the Detail Type, select Bad debts.
5. In the Name field, enter “Bad debts.” Then, click Save and Close.

Then, let's create a bad debt item. Here's how: 

1. Go back to the Settings menu, then select Products and Services.
2. Select New, and then Non-inventory.
3. In the Name field, enter “Bad debts.”
4. From the Income account drop-down menu, select Bad debts.
5. Select Save and Close.

After that, follow steps 4 and 5 to create a credit memo for the bad debt and apply it to the invoice outlined in this help article: Write off bad debt in QuickBooks Online.

For future reference, visit our QuickBooks Online Help Articles to learn more about managing your customers and income, running reports, reconciliation, and a lot more.

Visit and post again at any time if you have additional concerns. I'll be here to be your QuickBooks guide.